Process for producing felted mineral wool insulation



June 28, 1932. G. D. SHAVER PROCESS FOR PRODUCING FELTED MINERAL WOOLINSULATION F iled Jan. 1, 1931 2 Sheets-Sheet 1 .m H V A. am w m5. W e.m M m e GM VI b June.2s,'1932.- G. D. SHAVER 1,865,049

PRCCESS FOR PRODUCING FELTED MINERAL WOOL INSULATION" Filed Jan. 7, 19512 Sheets-Sheet 2 Lu a \nvenTor. George D. Shaver by M M WW Afiys.

Patented June 28, 19 32 v UNITED ST TES GEORGE ID. SHAVER, OF KALAMAZOO, MICHIGAN, ABSIGNOR TO TEERMINSUL OORPO- PATENT! OFFICE RATIONOF AMERICA, 01 BOSTON, MASSACHUSETTS, A CORPORATION OF MASSA- PROCESSFOR PRODUCING FELTED MINERAL WOOL INSULATION I Applicationnled January7, 1931. Serial No. 507,268.

This invention relates to improvements in felted mineral wool insulationand to processes andapparatus for producing the same.

The principal object of the invention is to provide a material havinginsulating properties against heat and cold, and wh1ch also desirably iseffective insulation against the passage of electric currents, and whichalso possesses efiicient sound-absorbing properties.

More particularly the object of the invention is to provide aninsulation composed wholly or mainly of mineral wool so felted as toproduce an occluded cellular structure which will effectively preventthe circulation of air through the material and thereby offer a maximumresistance to the transmission of heat or cold therethrough.

The term mineral wool is used herein as including rock wool, slag wool,or other mineral wools. I

A further object of the invention is to provide a process .for producingmineral wool insulation, of the character above specified in the form ofcontinuous sheets as distinguished from usual methods of producing assent clean-cut edges, such blocks being selectively of uniform size orof different sizes as may be desired.

vide. suitable apparatus for performing the process necessary to producethe article above described.

-- These and other objects and features of the invention will more fullyappear from cal pressure or by air pressure. The particular limitationsof such blocks or bricks are in respect to size which is limited by thedimensions of the mould in which the material'is compressed and b theimpossibility of satisfactorily controlllngthe densities and thicknessesof the product. By the present invention an improved insulation may bemade of mineral wool, with or without the inclusion of other fibres, andwith or without size or other binders.

. By the present process also the sheets or blocks are made of such acharacter as to be self-supporting without the use of fibres or otherbinders.

The fibres of commercial rock wool contain more or less shot which areattached to the ends of thefibres, or have been detached from the same,the presence of which is undesirable in the insulation. By the presentprocess substantially all'of such shot are removed as are also otherheavy foreign materials which are accidentally intermingled with thewool fibres, during the course of its manufacture.

The process of producing mineral wool insulation in'sheet form comprisesbroadly the mixing of masses of mineral wool with a relatively largequantity of liquid, preferably water, which may or may not contain asuitable binder, agitating the mixture to individu'alize the wool fibresand to disperse them uniformly throughout the liquid, and also tomaintain the fibres in suspension therein, then gradually andprogressively felting the fibres while beingheld in suspension to pro-.duce a continuous sheet. A further object of the invention is to pro-'it is desirably caused'to flow preferablyin a sinuous course at: avelocity sufiicient to maintain the fibres in suspension in the liquid,but to permit the shot and. heavy impurities to settle therefrom.

The fibres may be progressively and continuously felted in any suitablemanner, preferably by first causing the accumulation of a travellingmass of fibres in a direction counter to the direction of flow of thecurrent of liquid, suspending the fibres so that additional fibres aregradually and progressively collected by the projecting ends of thepreviously felted fibres until a sheet is formed of a desirablethickness. Such a sheet may be continuously produced and cut in suitablelengths for use as insulation. However, the surface of the sheet thusproduced may be more or less uneven and irregular. A further step in theprocess consists in surfacing and compressing the sheet formed as abovedescribed to present a smooth matted surface stratum. Such a stratum maybe produced in any suitable manner as by carrying the sheet over asuitable support with a roller, or other device, spaced apart therefroma predetermined distance sutlicient to determine the desired.

thickness of the sheet, the roller being driven either at substantiallythe same speed, or at a slightly greater speed than the speed ofmovement of the sheet, or the sheet may be surfaced and compressed bypassing it beneath a suitable blade or between endless belts, or it maybe similarly surfaced by suitable hand tools.

Desirably completion of the surfacing may be performed by other meansengaging both surfaces of the sheet and exerting a slight compressionand frictional action thereupon such as will lay the fibres of thesurface zone in substantially the same plane without materiallyaffecting the cellular structure of the central portion of the sheet.

By the process above described a self-supporting sheet may be formed ofmineral wool 4 fibres without the inclusion of any other ilbrous orother binding material.

A further step in the process comprises trimming the sheet and severingthe same longitudinally hydraulically by small jets of water under highpressure projected upon the sheets in the desired line or lines ofseverance. Such jets may be held stationary while the continuouslyformed sheet is passmg beneath them and the, line of severance willpresent clean-cut sharp edges. Thus the sheet may be cut longitudinallyinto strips of any desired width.

Another step in the-process consists in severing the continuouslyproduced sheet transversely. This may be accomplished hvdraulically byproviding a small water jet of high pressure and moving the sametransversely of the sheet either when the same is stationary or duringthe continuous progress thereof as it is being made in the manner abovedescribed. Thus the sheet may be cut into slabs or into blocks of anydesired planar dimensions.

V The sheets or the blocks or slabs thus constructed may be subjected toany desirable drying operation which will evaporate the water containedin the interstices of the sheet.

The body of the sheet thus produced after the water has been evaporatedtherefrom is of such fine interstitially cellular construction thatcirculation of air through or within the sheet is practically inhibited.

Inasmuch as the insulation thus produced comprises fibrous materialwhich itself is of high insulating properties, assembled as to preventcirculation of air through or within the sheet, practically idealinsulating properties are attained.

bviously insulation of this character is resistant to the passage of anelectric current as the mineral wool, which is in effect glass, is anexcellent dielectric and the dead air spaces of the cells are themselvesexcellent electrical insulators.

The insulating material thus formed is absorbent to sound waves andtherefore is adapted for use in acoustical and sound-deadening uses.

The process above described may be performed manually or by suitableapparatus such as that illustrated in the accompanying drawings. J

In the drawings:

Fig. 1 is a diagrammatic view of suitable apparatus for making mineralwool insulation in accordance with the process above described;

Fig. 2 is a detail plan view of a preferred mechanism for completing thesurfacing of the continuously produced sheet and for dividing the sameinto strips and/or blocks or slabs; and, I

Fig. 3 is a detail view of the inter-relation between the clutchoperating the cut-off device and the gate which predetermines the lengthsevered fromthe continuously travelling sheet;

The apparatus illustrated in the accompanying drawings comprises aseparator 1 having a hopper into which the mineral wool is introduced, adownwardly inclined bottom 2, and a. reciprocable screen 3 which isadapted to agitate the wool fed into the separator and to separate theshot therefrom which passes through the screen into the chamber formedby the sloping bottom 2. This cleaner, which is particularly desirablefor use with dirty wool, may, of course, be replaced by other deviceswhich will perform the same service, or may be dispensed with entirelywhere clean wool is employed Without effecting the process.

The wool, which passes from the separator l, is delivered in masses ofvarious sizes to a tank 4 containing a predetermined large quantity ofliquid, preferably water, sulficient to produce a batch of mixture forfurther treatment. In practice, it is found that the relativeproportions of six hundred fifty pounds of mineral wool to approximatelytwelve thousand pounds of water, (approximately one thousand fivehundred gallons), produces a satisfactory mixture.- The liquid may besupplied to the tank 4 in any suit-able manner asfrom a storage tank 5located at a I higher level than the tank. The tank is promaintained asufiicient length of time to disperse the individualized fibresuniformly throughout the liquid when the batch is ready for furthertreatment.

After the fibres have been thus individualized and suspended in theliquid, the mixture is dropped through a valve 6 into a storage tank 7also containing agitators 8 which are driven at a suflicient speed tomaintain the individualized fibres in suspension in the liquid. When theagitating tank 4 has been emptied, it is ready for a new batch ofmineralwool fibres and liquid as above described.

From the tank 7 the mixture is forced by a pump 9 to a control box 10from which it passes'through a pipe having a valve 11 to a rifiie trough12. The excess of mixture de livered by the pump 9 to the box 10 flowsovera partition in said box and is. returned there i from the storagetank, thi's'additional liquid from through a suitable pipe to thestorage tank 7. The valve 11 is in'eifect a submerged orifice subject toa constant head, and passes a constant quantity of the mixture from theflow box to the'riflle trough '12. per unit of time. y

The mixture entering the rifile trough 12 is further diluted byadditional liquid delivered serving to provide a further dispersion ofthe individualized fibres. 1

The riflie trough 12, which is slightly inclined, is provided with asuitable series of riffle boards 13 which cause the mixture to flow inan undulated path at a uniform velocity sufficient to maintain thefibres in suspension, but to permit the shot and heavy impurities tosettle from the'mixture, but, at a velocity insuflicient to carry theshot and heavy impurities over the baflles, so that the shot andimpurities will settle to the bottom of the riflle trough from whichthey can be removed when convenient in any suitable manner.

The action taking place in therifile trough 12, with the additionalwater supplied thereto, is an important factor in making a clean 3:18?of mineral felt almost entirely. free of s o The mixture then passesfrom the rifile trough 12 into ahead box 12-0 of considerably greaterwidth than that of the rifile trough, from which it is delivered in astream of substantially uniform depth across the width of the head boxinto the tank 14 of a continuous filter. v I

The .filterdrum comprises a cylinder 15 having a screen surface anddivided into a serles of peripheral hollow sections forming suctionboxes connected by pipes to the hollow shaft of the filter drum.Suitable valves are provided to apply suction to the sections duringtheir submergence and until just after the boxes pass across thevertical axial plane of the filter.

Suction is applied to the commutating valves'through a pipe 16 whichcommunicates with a separating tank 17 the upper portion of which isconnected to a suitable air pump 18. A pipeleads from the bottom of theseparating tank to a pump 19 from which the water, which is deposited ina separator tank,

is pumped through a suitable pipe preferably through an intermediatetank to the storage tank 5 which desirably is provided with a valve pipe21 for delivering water to the agitating tank 4, as above described.

The additional water supplied to the rifile trough is controlled by avalve 20 in a pipe leading through the intermediate tank, so that adesirable solution mixture may 'be maintained in the filter tank 14.

In the operation of the filter the sheet begins to form upon the filterscreen. as soon as the suction boxes are released to the suction of thepipe 16 through the commutating valves. The fibres next to .the screenare drawn tightly thereto, while fibres further out from the screenremain fuzzed out in a loose formation in all directions in the mixture.The beginnings of the sheet, together with the drum, and supported uponthe surface of' the drum, are travelling at this time in an upwarddirection.

The'stock or mixture from the head box 12 a is continuouslyfallingdownwardly into the filter tank 14 and the fibres in thisincomward current of water continuously passing through the sheet causelater fibresto be continuously interwoven, felted, and commingled in alldirections before in turn being laid down' upon the growing face of thesheet by water passage through the sheet and the sure of continuouslyaddative wool. As shown in Fig. 1 of the drawings, the

pres-- felting begins at approximately the lowest portion of the filterdrum and increases in thickness as the suction box of the drum passesupwardly through the mixture, finally emerging from the level thereof asa very looselywoven felted sheet 22. This sheet 22, due to the processof formation above described, and the practically ideal interweaving ofits fibres, is the improved mineral wool felt.

Desirably means are provided to compress the sheet to approximately thedesired thickness. This is accomplished in the construction illustratedby providing a roller 23, which may be adjustably mounted and located apredetermined distance from the periphery'of the filter drum. The roller23 exerts a slight squeezing action upon the sheet, thus strengtheningand stiffening it before it leaves the filter drum, so that the sheetmay be removed from the drum without the use of a doctor blade or usualair pressure means for disengaging it from the drum, thus enabling it tobe delivered upon a series of rolls 24 to suitable surfacing rolls 25.

The surfacing rolls 25 are arranged in pairs and adjustably. spacedapart.

Suitable means are provided for driving the rolls at selected dilferentspeeds, as, for example, by a countershaft 26 suitably geared to theshafts of the lower set of rolls and driven by a belt through a conepulley 27.

The density and thickness of the sheet may be controlled by the settingof the rolls 25, the speed of the filter drum, which likewise may bedriven at different desirable speeds through a cone pulley 28 or othersuitable mechanism, and by regulation of the valve 11 which controls thesupply of mixture to the ritlle trough and from it to the filter tank.

It is obvious that if the filter drum is driven continuously at apredetermined speed, and the valve opened to deliver stock at apredetermined rate, a greater pressure of the rolls, caused by adjustingthe same toward each other, would produce a thinner and more densesheet. 1

It is also obvious that-in the absence of the pressure rolls 25,regulation of the flow of the mixture may be made to produce sheets ofpredetermined different thicknesses. If the valve 11 is set to providefor a predetermined delivery of mixture or stock, regulation in thespeed of the filter may be made to produce sheets of different.predetermined thickness. A more accurate regulation of the thickness maybe produced by correlating the rate of flow of the mixture and the rateof felting to produce sheets of different predetermined thickness. Byproviding a desired setting for the rolls to produce a sheet ofpredetermined thickness, and varying the rate of flow of the mixture,sheets of different predetermined densities may be produced.Furthermore, the density of the sheet may be determined by providing auniform flow of the mixture or stock from the flow boxes and varying thespeed of the filter drum. Thus by correlating the adjustment of therolls, the speed of the rolls, the speed of the felting drum, and therate of flow, the thickness and density of the sheet of insulation maybe accurately controlled to produce a sheet of a desired uniformthickness and uniform density.

The sheet delivered from the pressure rolls is carried by supportingrolls 29, preferably into the field of mechanism for trimming the sheet,and for cutting the same longitudinally into strips and/or transverselyint-o slabs or blocks. In the preferred con-v struction illustrated,(Fig. 2) the cutting mechanism comprises a stand 30 which carries a pipe31 supplied with water under high pressure. Flexible pipes 32, branchingfrom the pipe 31', lead to nozzles 33 adjustably supported upon atransverse bar 34. The nozz cs 33 may be adjusted to any desiredposition transversely of the direction of movement of the sheet andproject fine cutting jets of water directly upon the sheet. Theoutermost of these jets may be employed to trim't-he sheets, whileintermediate jets will serve to cut the continuously travelling sheetlongitudinally into strips.

Suitable means may be provided for cutting the sheet or stripstransversely. In the construction illustrateda frame is providedcomprising tracks 35 and 36 extending transverscly of the sheet anddownwardly extend ing legs 37 and 38 provided with rolls which engagethe upper and lower edges of tracks 39- extending longitudinally of themachine adjacent the edges of the sheet. A carriage 40 is reciprocablymounted upon the frame and carries a water jet, or preferably aplurality of water jets 41 which are suitably connected to the pipe 31by a flexible hose 42.

Preferably two jets are provided, one located at the end of the carriagewhich passes over the edge of the sheet, and the other jet at theopposite end of the carriage and approximately in the vertical plane ofthe longitudinal axis of the sheet, so that when the carriage is movedacross the sheet, the sheet will be severed throughout its entire width.

The frame may be reciprocated in any suitable manner in synchronism withthe movement of the sheet. In the preferred construction a bar 43, whichis connected to the carriage, is provided with a rack 44 which engages asuitable pinion 45 upon a clutch 46 one of the members of which is fixedto one of the lower compression roll shafts. The extent of movement ofthe carriage may be determined by suitable clutch-controlling means. Inthe preferred construction illus trated such controlling means comprisesa bar 47 which is adjustably mounted upon the rear track 37 of the frameand having at its end a pivotally mounted switch member 48 adapted tocontrol an electric circuit 49 leading to a magnetic clutch-operatingdevice 50.

Any suitable means, such as a counterweight, not shown, may be providedfor re- 7 turning thevframe after disengagement of the clutch members.

In operation, therefore, when the switch member 48 is engaged by the endof the sheet, the switch of the electric circuit 49 Will be closed,thereby actuating the magnetic clutch-operating device to causeengagement of the clutch members, thus causing the gear 45 to drive therack bar 43 and advance the travelling frame in synchronism with themovement of the sheet.

Any suitable means may be provided to limit the movement of thetravelling frame,

when engaged by a member of the travelling frame to open the electriccircuit 49, thereby disen aging the clutch-members and permitting t etravelling frame to be returned by In operation, therefore, the framewill travel longitudinally in synchronism with.

the direction of movement of the sheet.

Suitable valves are provided for controllin the jets 41.

he cutting of the sheet, therefore, into 85 longitudinal strips isproduced by the jets pro ected from the nozzles '33 and the trans versecuttingof the sheet or strips into slabs or blocks is producedflby thereciprocation of the jets supported upon the carriage transversely ofthe direction of movement of the sheet, as the sheet travels upon itssupporting rolls. 'By thus hydraulically cutting the sheet, smooth edgesare produced the margins of which are not distortedor condensed as inusual methods of cutting sheets by knives, saws, or otherwise. 1 4 l Thenarrow edge zones of the blocks when thus hydraulically severed from thesheet are of relatively greater flexibility than the body of the blockso that when the blocks are laid edge to ed e and forced toward eachother the edge fi res of theblocks will become interlaced and willproduce a finel cellular structure having an insulating va ue whichcompares quite favorably with that of the body of the adjacent blocks.Where a binder, which is soluble in water, such as starch, is employed,the actionof the hydraulic jets in cutting. the sheet into slabs orblocksdissolves and carries away-the majority'o f-the binder along anarrow zone adjacentlto theout, thereby makin the edges of the sheetmore flexible than thehody thereof after the drying operation, sopressuch as aswitch 51 in the circuit 49, adapted the. action of thecounterweight, not shown.

mechanism for traversing it transversely ofsure applied to the sheetsinassembling them edge to edge, causes the fibres of the contactingrelatively flexible zone to interlace and embed with each other, so thatthe assembled sheet presents uniform insulating qualities throughout.Where binders insoluble in water are employed, a similar flexibility maybe'imparted to the edges of the sheet by cutting the sheet by jets of,or containing a sufficient quantity of a liquid solvent of the hinder,to remove a substantial portion of the coating of the fibres in thenarrow zone adjacent to the cut and thereby reduce the bonding action ofthe coating.

When the transverse cutting of the sheet 80 has been completed by thejets 41, the cut-ofl", portion of the sheet is removed and thetravelling frame is returned in the manner above described to itsinitial position where it remains until the new end of the sheet strikesthe switch 48, when the cycle is repeated.

The slabs or blocks, after having been'cut olf, are removed'and dried inany conventional manner as on rack cars placed in ovens, T orcontinuously driven rollers or travelling belts passing through theovens, the ovens being heated in any desired manner.

- By reason of the present invention, therefore, continuous sheets ofrock wool insulation of indeterminate length may be produced, or blocksor slabs of any desired size may be made. The sheets thus produced maybe of any desired uniform thickness and ofany desired densityd V Theaction of the pressure rolls 25 upon the sheet, when driven at aslightly greater speed than the sheets, serves to lay-down the .fibresupon the surface zones of the sheets in such a manner as to produce acomparatively smooth and condensed surface which lends rigidity to thesheet and makes it selfsustaining.

By introducing into the mixture a suitable binder, such as starch orasphaltum, adapted to coat the individual fibres before they areassembled in the felting operation, sheets of a vdesired stifiness maybe produced without substantially affecting the occluded cellularstructure thereof. a

Having thus described the invention, what is claimed as new, and desiredto besecured by Letters Patent, is: e V l. The process of producingmineral wool insulation in sheet form which comprises mixing masses ofmineral wool with a relatively large quantity of liquid, agitating the 7mixture to individualize the wool fibres,to disperse the'fibrespniformly throughout the liquid and to maintain the fibres in suspensiontherein, causing the mixture to'flow at a uniform rate sufiicientlyrapid tomaintain the fibres in suspensiomand gradually and progressivelfelting thefibres while held in suspension y the flowing liquid toproduce a continuous sheet of substantially uniform thickness.

2. The process of producing mineral woolsuspension, but to permit theshot and heavy impurities to settle therefrom, and thereafterprogressively felting the fibres while held in suspension by the flowingliquid to produce a continuous sheet of substantially uniform thickness.

3. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate sufficient to maintain the fibres in suspension thereaftergradually and progressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, and regulating therate of flow of the mixture to produce a sheet of substantially apredetermined uniform thickness.

4.. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate while maintaining the fibres in suspension, thereafter graduallyand progressively felting the fibres while held in suspension by theflowing liquid to produce a continuous sheet, and regulating the rate offelting to produce a sheet of substantially a predetermined uniformthickness.

5. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate sufficient to maintain the fibres in suspensi0n,'thereaftergradually and progressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, and correlating therate of flow of the mixture and the rate of felting to produce a sheetof substantially a predetermined uniform thickness.

6. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in-suspension therein, causing the mixture to flow at a uniformrate sufficient to maintain the fibres in suspension, thereaftergradually and pro gressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, and surfacing thewet felted sheet by friction and pressure and compressing it to apredetermined thickness.

7. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate sufiicient to maintain the fibres in suspension, thereaftergradually and pro gressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, correlating therate of flow of the mixture to the predetermined thickness to produce asheet of predetermined density and surfacing the wet felted sheet andcompressing it to a predetermined thickness.

8. The process of producing mineral Wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate suflicient to maintain the fibres in suspension, thereaftergradually and progressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, correlating therate of felting to the predetermined thickness to produce a sheet ofuniform density, surfacing the wet felted sheet by friction andcompressing it to a predetermined thickness.

9. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral Wool with a relatively large quantityof liquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate sufficient to maintain the fibres in suspension, thereaftergradually and progressively felting the fibres while held in suspensionby the flowing liquid to produce a continuous sheet, surfacing the wetfelted sheet by friction and compressing it to a predeterminedthickness, and correlating the rate of flow of the mixture, the rate offelt- 7 ing, and the degree of compression to tinuous sheet, sur acingthe wet felted sheet by friction and compressing it to a p edeterminedthickness, and hydraulically trimming the edges of the wet sheet.

11. The process of producing mineral wool insulation in sheet form whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the 7 mixture to individualize the wool fibres, to

disperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformrate suflicient to maintain the fibres in suspension, gradually andprogressively felting the fibres while held in suspension by-the flowinliquid to produce a continuous sheet, sur acing the wet felted sheet byfriction and compressing it to a predetermined thickness, hydraulicallytrimming the edges of the wet sheet, and hydraulically cutting the wetsheets longitudinally, as continuously produced, into strips.

, 12. The process of producing insulation blocks of mineral wool whichcomprises mixing masses of mineral wool with a relatively large quantityof liquid, agitating the mixture to. individualize the wool fibres,'todisperse the fibres uniformly throughout the liquid and to maintain thefibres in suspension therein, causing the mixture to flow at a uniformvrate suflicient to maintain the fibres in suspension, gradually andprogressively felting the fibres while held in suspension by the flowingliquid to produce a continuous sheet, surfacing the wet felted sheet byfriction and compressing it to a predetermined thickness, andhydraulically severing the sheet transversely at predetermined desiredintervals to produce slabs or blocks.

13. The process of producing mineral wool insulation which comprisesmixing masses of mineral wool with a relatively large quantity ofliquid, agitating the mixture to individualize the wool fibres, todisperse the fibres uniforml throughout the liquid and to maintain thebres in suspension therein, causing the mixture to flow at a uniformrate suflicient to maintain the fibres in suspension, gradually andprogressively felting the fibres while held in suspension by the flowingliquid to produce a continuous sheet, surfacing the wet felted sheet byfriction and compressing it to a predetermined thickness, hydraulicallytrimming the edges of the wet sheet, hydraulically cutting the wetsheets longitudinally, 'as continuously produced, into strips, andhydraulically severing the sheet-s transversely at predetermined desiredintervals to produce slabs or blocks. I

In testimony whereof, I'have signed my name to this specification.

GEORGE .D. SHAVER.

